This application is based on application Ser. No. 2001-348373, filed in Japan on Nov. 14, 2001, the contents of which are hereby incorporated by reference.
1. Field of the Invention
The present invention relates to a cylinder disabling control apparatus of a multi-cylinder engine which has a catalytic converter for purifying exhaust gas, and more specifically, it relates to a cylinder disabling control apparatus for a multi-cylinder engine which is capable of efficiently controlling disabled or stopped cylinders immediately after starting of the engine until a catalyst in the catalytic converter is activated (i.e., until a predetermined time has elapsed) according to the temperature of engine cooling water at the time of the engine starting.
2. Description of the Prior Art
Conventionally, a variety of cylinder disabling or cut-off control apparatuses for multi-cylinder engines have been proposed which, for the purpose of improving fuel economy, perform cylinder disabling control (i.e., some of cylinders being stopped or disabled) in accordance with the operating conditions of an engine (e.g., a warm up condition) thereby to save and reduce the amount of injected fuel, as disclosed for example in Japanese Patent Application Laid-Open No. 10-169479, etc.
On the other hand, environmental problems have gotten a lot of attention in recent years, and exhaust emissions control on engines is becoming severe year by year, too.
Thus, in order to cope the exhaust emissions control, technologies for postprocessing exhaust gas with a catalytic converter (hereinafter, also simply referred to as a xe2x80x9ccatalystxe2x80x9d) are making great advances.
Today, exhaust gas after a catalyst has been activated can be purified substantially to a satisfactory extent, but it is difficult to reduce the amount of harmful or untreated components in the exhaust gas during a period of time immediately after starting of an engine until the catalyst is activated, thus giving rise to a big problem. In particular, the greater the displacement of the engine, the greater becomes the importance of a demand for purifying the exhaust gas at the time of engine starting.
With the known cylinder disabling control apparatuses for multi-cylinder engines, exhaust gas can be satisfactorily purified after the activation of the catalyst, however, there has been a problem that exhaust gas could not be purified for a period of time after starting of an engine until the catalyst is activated, so the exhaust emissions control or regulations stipulated by governments in advanced countries could not be cleared or satisfied immediately after the engine starting.
The present invention is intended to solve the problem as referred to above, and to this end, special attention has been paid to the fact that there will be no problem in terms of driver""s feeling even if cylinder disabling control is effected (i.e., some of cylinders are stopped or disabled) at a time such as an engine starting period, idling time and the like in which required torque of the engine is comparatively limited. Accordingly, in view of this fact, the object of the present invention is to provide a cylinder disabling control apparatus for a multi-cylinder engine which is capable of efficiently reducing the engine exhaust gas and hence harmful components contained therein immediately after starting of the engine by performing cylinder disabling control for a period of time in which a catalyst in a catalytic converter is in an inactivated state.
Bearing the above object in mind, there is provided a cylinder disabling control apparatus for a multi-cylinder engine including: a variety of sensors for detecting operating conditions of an engine having a plurality of cylinders; a catalytic converter for purifying exhaust gas of the engine; and a cylinder disabling control means for performing cylinder disabling control on at least one specific cylinder among the plurality of cylinders by inhibiting fuel supplied to the at least one specific cylinder in accordance with the engine operating conditions. The variety of sensors includes a water temperature sensor for detecting a temperature of cooling water of the engine. When the temperature of cooling water upon starting of the engine is equal to or higher than a first predetermined temperature, the cylinder disabling control means performs cylinder disabling control on the at least one specific cylinder immediately after the starting of the engine until a predetermined time has elapsed.
Therefore, a cylinder disabling control apparatus for a multi-cylinder engine which is capable of efficiently reducing the engine exhaust gas at a time such as an engine starting period can be provided.
The above and other objects, features and advantages of the present invention will become more readily apparent to those skilled in the art from the following detailed description of preferred embodiments of the present invention taken in conjunction with the accompanying drawings.